In an organic light-emitting diode, the light generated by said organic light-emitting diode is partly coupled out directly from the organic light-emitting diode. The rest of the light is distributed into various loss channels, as is illustrated in an illustration of an organic light-emitting diode 100 in FIG. 1. FIG. 1 shows an organic light-emitting diode 100 having a glass substrate 102 and a transparent first electrode layer 104 for example composed of indium tin oxide (ITO) and arranged on said glass substrate. Arranged on the first electrode layer 104 is a first organic layer 106, on which an emitter layer 108 is arranged. A second organic layer 110 is arranged on the emitter layer 108. Furthermore, a second electrode layer 112 for example composed of a metal is arranged on the second organic layer 110. An electric current supply 114 is coupled to the first electrode layer 104 and to the second electrode layer 112 such that an electric current for generating light is passed through the layer structure arranged between the electrode layers 104, 112. A first arrow 116 symbolizes a transfer of electrical energy in surface plasmons into the second electrode layer 112. A further loss channel can be seen in absorption losses in the light emission path (symbolized by means of a second arrow 118). Light not coupled out from the organic light-emitting diode 100 in a desired manner is for example a portion of the light which arises on account of a reflection of a portion of the generated light at the interface between the glass substrate 102 and air (symbolized by means of a third arrow 122) and on account of a reflection of a portion of the generated light at the interface between the first electrode layer 104 and the glass substrate 102 (symbolized by means of a fourth arrow 124). That portion of the generated light which is coupled out from the glass substrate 102 is symbolized by means of a fifth arrow 120 in FIG. 1. Illustratively, therefore, for example the following loss channels are present: light loss in the glass substrate 102, light loss in the organic layers and the transparent electrode 104, 106, 108, 110 and surface plasmons generated at the metallic cathode (second electrode layer 112). These light portions cannot readily be coupled out from the organic light-emitting diode 100.
For coupling out substrate modes, so-called coupling-out films are conventionally applied on the underside of the substrate of an organic light-emitting diode, and can couple the light out from the substrate by means of optical scattering or by means of microlenses. It is furthermore known to structure the free surface of the substrate directly. However, such a method considerably influences the appearance of the organic light-emitting diode. This is because a milky surface of the substrate arises as a result.
For coupling out the light in the organic layers of the organic light-emitting diode, various approaches currently exist, but as yet none of these approaches has matured to product readiness.
These approaches are, inter alia:                Introducing periodic structures into the active layers of the organic light-emitting diode (photonic crystals). However, these have a very great dependence on wavelength since the photonic crystals can only couple out specific wavelengths.        Using a high refractive index substrate for directly coupling the light of the organic layers into the substrate. This approach is very cost-intensive on account of the high costs for a high refractive index substrate. Furthermore a high refractive index substrate relies on further coupling-out aids in the form of microlenses, scattering films (each having a high refractive index) or surface structurings        
Furthermore, a thermotropic glass layer for adapting the transparency of a window glass is known and available from the company Tilse under the designation Solardimc®.